JP2018168704A - Control device for engine - Google Patents

Abstract

To provide a control device for an engine capable of suppressing occurrence of a torque shock after fuel supply stop caused by engine speed reduction during a reduced-cylinder operation.SOLUTION: A control device for an engine comprises: operation condition discrimination means for discriminating an execution condition of a reduced-cylinder operation of the engine including multiple cylinders; speed reduction fuel supply stop discrimination means for discriminating a speed reduction fuel supply stop condition; and cylinder stop control means including fuel control means which controls fuel supply to the engine, for switching from an all-cylinder operation to the reduced-cylinder operation in a case where the execution condition of the reduced-cylinder operation is established. In a case where establishment of the speed reduction fuel supply stop condition during the reduced-cylinder operation is discriminated by the operation condition discrimination means and the speed reduction fuel supply stop discrimination means, the fuel control means stops the fuel supply, and the cylinder stop control means switches from the reduced-cylinder operation to the all-cylinder operation.SELECTED DRAWING: Figure 9

Description

  The present invention relates to an engine control device, and more particularly to an engine control device capable of executing a reduced-cylinder operation in which operation of some cylinders among a plurality of cylinders is stopped.

  2. Description of the Related Art Conventionally, for the purpose of improving fuel efficiency, an engine control device that can perform a reduced-cylinder operation that stops operation of some of a plurality of cylinders is known. Such an engine control device controls to close the intake and exhaust valves of the cylinders that are stopped when the execution condition of the reduced cylinder operation is satisfied. When the execution condition of the reduced cylinder operation is not satisfied, the operation of the idle cylinder is resumed and the entire cylinder operation is resumed. The engine speed and the like are set as an execution condition for the reduced cylinder operation.

  When all-cylinder operation and reduced-cylinder operation are switched, the engine output changes due to a change in the number of operating cylinders, and torque shock occurs. Therefore, the amount of air sucked into each cylinder is adjusted to suppress the occurrence of torque shock.

  When the vehicle travels, the engine speed varies depending on surrounding traffic conditions. For example, when the vehicle decelerates, the driver returns the accelerator pedal to decelerate the engine, uses engine braking by the engine whose fuel supply has been stopped, and depresses the brake pedal when decelerating faster. At the start of this fuel supply stop, torque fluctuations occur because torque fluctuations increase.

  Therefore, the ignition timing control device for a variable cylinder internal combustion engine disclosed in Patent Document 1 delays fuel supply stop and performs ignition timing retard to suppress the occurrence of torque shock.

Japanese Patent No. 396358

  By the way, if the fuel supply is stopped and the engine continues to decelerate, the engine stops. Therefore, the fuel supply return rotation speed is set so that the engine does not stop. Further, the lower limit rotational speed for switching between the reduced-cylinder operation and the all-cylinder operation is set in the vicinity of the fuel supply return rotational speed in order to widely set the reduced-cylinder operation region. Therefore, when using the engine brake during reduced-cylinder operation, if the engine decelerates while the fuel supply is stopped, switching to all-cylinder operation and returning to the fuel supply will continue at the same time, resulting in a large torque shock. There is a risk of doing.

  An object of the present invention is to provide an engine control device that can suppress the occurrence of a torque shock after stopping fuel supply due to engine deceleration during reduced-cylinder operation.

  The invention according to claim 1 is an operation condition determining means for determining an execution condition of a reduced cylinder operation of an engine having a plurality of cylinders, a deceleration fuel supply stop determining means for determining a deceleration fuel supply stop condition, and a fuel to the engine An engine control device comprising: a fuel control unit that controls supply; and a cylinder deactivation control unit that switches from all-cylinder operation to reduced-cylinder operation when an execution condition for reduced-cylinder operation is satisfied. When the deceleration fuel supply stop determination unit determines that the deceleration fuel supply stop condition during the reduced cylinder operation is satisfied, the fuel control unit stops the fuel supply, and the cylinder deactivation control unit starts from the reduced cylinder operation. It is characterized by switching to tube operation.

  With the above configuration, when the deceleration fuel supply stop condition is satisfied during execution of the reduced cylinder operation due to the execution condition of the reduced cylinder operation, the operation is switched to the all cylinder operation so that the switching to the all cylinder operation and the fuel supply return are not continued. The occurrence of torque shock can be suppressed.

According to a second aspect of the present invention, in the first aspect of the invention, the fuel control means returns the fuel supply when the engine decelerates to a fuel supply return rotation speed or less, and the fuel supply return rotation speed decreases the fuel supply return rotation speed. It is characterized in that it is set in the vicinity of the engine speed lower limit in the cylinder operation execution conditions.
With the above configuration, the engine continues to decelerate after switching to all-cylinder operation after the deceleration fuel supply stop condition is satisfied, and the fuel supply returns after decelerating below the fuel supply return rotation speed. Thus, the occurrence of torque shock can be suppressed by preventing the fuel supply return from continuing. Further, it is possible to set a wide engine speed range where deceleration fuel supply can be stopped.

According to a third aspect of the present invention, in the second aspect of the present invention, when the accelerator pedal is depressed before the fuel supply is returned by the fuel control means after the reduced cylinder operation is switched to the all cylinder operation, the reduction is performed. It is characterized by switching to tube operation.
With the above-described configuration, after switching to the all-cylinder operation when the deceleration fuel supply stop condition is satisfied during the reduced-cylinder operation, the operation is returned to the reduced-cylinder operation in a state where the fuel supply is stopped.

A fourth aspect of the invention is characterized in that, in the third aspect of the invention, after switching to the reduced-cylinder operation, the fuel control means returns the fuel supply.
With the above configuration, switching to the all-cylinder operation and the return of fuel supply are not continuous, so that torque shock can be suppressed.

  According to the engine control apparatus of the present invention, it is possible to suppress the occurrence of a torque shock after the deceleration fuel supply is stopped due to engine deceleration during the reduced cylinder operation.

It is a schematic plan view which shows the whole structure of an engine. It is a longitudinal cross-sectional view of an engine. It is sectional drawing which shows a valve stop mechanism, (a) is a pivot part locked state, (b) is a state before a pivot part transfers to a lock release state, (c) shows a pivot part lock release state. It is the schematic which shows the structure of an oil supply apparatus. It is a block diagram which shows the control system of an engine. It is the map which set the all cylinder operation area | region and the reduced cylinder operation area | region. It is a flowchart which shows the operating condition determination processing content. It is a time chart which shows the time change of each parameter. It is a flowchart which shows control of the deceleration fuel supply stop by the engine control apparatus which concerns on an Example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The following description is an example in which the present invention is applied to an engine control device, and does not limit the present invention, its application, or its use.

  Embodiments of the present invention will be described below with reference to FIGS.

(Entire engine configuration)
As shown in FIGS. 1 and 2, the engine 1 is, for example, an in-line four-cylinder gasoline engine in which a first cylinder to a fourth cylinder are sequentially arranged in series, and is mounted on a vehicle such as an automobile. In the engine 1, a head cover 2, a cylinder head 3, a cylinder block 4, a crankcase (not shown), and an oil pan 5 (see FIG. 4) are connected to each other vertically.

  A piston 6 slidable in four cylinder bores 9 formed in each cylinder block 4 and a crankshaft 7 rotatably supported by a crankcase are connected by a connecting rod 8. Combustion chambers 11 are formed in each cylinder by the cylinder bore 9, piston 6, and cylinder head 3 of the cylinder block 4. Each combustion chamber 11 is provided with an injector 12 and a spark plug 13, and ignition is performed in the order of the first cylinder → the third cylinder → the fourth cylinder → the second cylinder.

  The intake system of the engine 1 includes an intake port 21 that communicates with the combustion chamber 11, an independent intake passage 22 that communicates with each of the intake ports 21, a surge tank 23 that is connected in common to the independent intake passage 22, The intake pipe 24 extends from the surge tank 23 to the upstream side. A butterfly throttle valve 25 capable of adjusting the amount of air introduced into the engine 1 via an air duct (not shown) is provided in the middle of the intake pipe 24, and the throttle valve 25 is driven in the vicinity thereof. An actuator 26 (electric motor) is installed.

  The exhaust system of the engine 1 includes an exhaust port 31 that communicates with the combustion chamber 11, an independent exhaust passage 32 that communicates with the exhaust port 31, a collective portion 33 in which the independent exhaust passages 32 are gathered, and the collective portion 33. It is comprised from the exhaust pipe 34 etc. extended in the downstream from. A butterfly type exhaust shutter valve 35 capable of adjusting the amount of exhaust gas discharged from the engine 1 is provided in the middle of the exhaust pipe 34, and an actuator 36 (for driving the exhaust shutter valve 35) is provided in the vicinity thereof. Electric motor) is installed.

  As shown in FIG. 2, the intake port 21 and the exhaust port 31 are provided with an intake valve 41 and an exhaust valve 51 for opening and closing each. The intake valve 41 and the exhaust valve 51 are urged in the valve closing direction (upward) by return springs 42 and 52, respectively, and swing by cam portions 43a and 53a provided on the outer periphery of the rotating cam shafts 43 and 53, respectively. Cam followers 44a and 54a, which are rotatably provided at substantially central portions of the arms 44 and 54, are pressed downward.

  The swing arms 44 and 54 swing around the tops of the pivot mechanisms 14a and 15a provided on one end sides of the swing arms 44 and 54, respectively, so that the intake valves 41 and the exhaust valves 51 are provided at the other ends of the swing arms 44 and 54, respectively. Is opened downward by being pushed downward against the urging force of the return springs 42 and 52.

  As the pivot mechanism 15a in the swing arms 44 and 54 of the second and third cylinders formed in the center of the engine 1 in the cylinder arrangement direction, the valve clearance is set by oil pressure (hereinafter simply referred to as oil pressure). A known hydraulic lash adjuster (hereinafter abbreviated as HLA) 15 that automatically adjusts to zero is provided. The pivot mechanism 15a has the same configuration as a pivot mechanism 14a of the HLA 14 described later.

  As shown in FIG. 2, HLA 14 with a valve stop mechanism having a pivot mechanism 14a is provided for swing arms 44 and 54 of the first and fourth cylinders formed at both ends of the engine 1 in the cylinder arrangement direction. Yes. The HLA 14 with a valve stop mechanism is configured so that the valve clearance can be automatically adjusted to zero by hydraulic pressure, similarly to the HLA 15.

  The HLA 14 stops the opening / closing operations of the intake valves 41 and the exhaust valves 51 of the first and fourth cylinders during the reduced-cylinder operation in which the operations of the first and fourth cylinders that are a part of all four cylinders of the engine 1 are stopped. . Further, the HLA 14 opens and closes the intake valves 41 and the exhaust valves 51 of the first and fourth cylinders during the all-cylinder operation in which all the four cylinders of the engine 1 are operated. The intake valves 41 and the exhaust valves 51 of the second and third cylinders operate in both the reduced cylinder operation and the all cylinder operation. That is, the intake and exhaust valves 41 and 51 of the first and fourth cylinders of the first to fourth cylinders of the engine 1 stop operating during the reduced cylinder operation, and the first to fourth cylinders operate during the all cylinder operation. The intake / exhaust valves 41 and 51 are operating. Note that the reduced-cylinder operation and the all-cylinder operation are appropriately switched according to the operating state of the engine 1 as described later.

Mounting holes 45 and 55 for inserting and mounting the lower end portion of the HLA 14 are provided in the intake side and exhaust side portions respectively corresponding to the first and fourth cylinders of the cylinder head 3. Further, in order to insert and mount the lower end portion of the HLA 15 in the intake side and exhaust side portions respectively corresponding to the second and third cylinders, mounting holes (not shown) similar to the mounting holes 45 and 55 are provided, respectively. It has been.
A pair of oil passages 71 and 73 are formed in the mounting hole 45, and a pair of oil passages 72 and 74 are formed in the mounting hole 55. The oil passages 71 and 72 are configured to supply hydraulic pressure for operating the valve stop mechanism 14b of the HLA 14, and the oil passages 73 and 74 are configured to supply hydraulic pressure for operating the pivot mechanism 14a of the HLA 14. Note that only the oil passages 73 and 74 communicate with the mounting hole of the HLA 15.

  As shown in FIG. 3A, the valve stop mechanism 14b is provided with a lock mechanism 140 that locks the operation of the pivot mechanism 14a. The lock mechanism 140 can advance and retreat with respect to the through-holes 141a formed at two locations opposed to each other in the radial direction on the side peripheral surface of the bottomed outer cylinder 141 that houses the pivot mechanism 14a slidably in the axial direction. A pair of lock pins 142 formed in the above are provided. The pair of lock pins 142 is biased radially outward by a spring 143. Between the inner bottom portion of the outer cylinder 141 and the bottom portion of the pivot mechanism 14a, a lost motion spring 144 that presses and urges the pivot mechanism 14a above the outer cylinder 141 is disposed.

  When the pair of lock pins 142 are fitted in the through holes 141 a of the outer cylinder 141, the pivot mechanism 14 a located above the lock pins 142 is fixed at the protruding position protruding upward. As a result, the top of the pivot mechanism 14a serves as a fulcrum for the swing of the swing arms 44 and 54. Therefore, when the cam portions 43a and 53a push the cam followers 44a and 54a downward by the rotation of the cam shafts 43 and 53, intake and exhaust are performed. The valves 41 and 51 are pushed downward against the urging force of the return springs 42 and 52 to open. That is, the all-cylinder operation is performed by fitting the pair of lock pins 142 into the through holes 141a.

  As shown in FIGS. 3 (b) and 3 (c), when the outer ends of the pair of lock pins 142 are pressed by the hydraulic pressure indicated by the black arrows, the pair of springs 143 resists the biasing force. The lock pin 142 moves backward in the radial direction of the outer cylinder 141 so as to approach. As a result, the pair of lock pins 142 comes out of the through hole 141a, and the pivot mechanism 14a moves together with the lock pin 142 to the lower side in the axial direction of the outer cylinder 141 to be in a valve stop state.

  The biasing force of the return springs 42 and 52 is set to be stronger than the biasing force of the lost motion spring 144. Therefore, when the cam portions 43a, 53a push the cam followers 44a, 54a downward by the rotation of the cam shafts 43, 53, the top portions of the intake / exhaust valves 41, 51 become fulcrums for swinging of the swing arms 44, 54. The pivot mechanism 14a is pushed downward against the urging force of the lost motion spring 144 while the intake and exhaust valves 41 and 51 are kept closed. That is, the reduced-cylinder operation is performed by bringing the pair of lock pins 142 into a state in which they are not fitted into the through-hole 141a.

(Oil supply circuit)
As shown in FIG. 4, the oil supply circuit includes a variable displacement oil pump 16 driven by the rotation of the crankshaft 7, and oil that has been boosted by being connected to the oil pump 16. And an oil supply passage 60 that leads to each hydraulic actuator. The oil supply passage 60 is an oil passage formed in the cylinder head 3 and the cylinder block 4 or the like. The oil supply passage 60 includes first to third communication passages 61 to 63, a main gallery 64, a plurality of oil passages 71 to 79, and the like.

  The first communication path 61 communicates with the oil pump 16 and extends from the discharge port 16 b of the oil pump 16 to the branch point 64 a in the cylinder block 4. The main gallery 64 extends in the cylinder row direction within the cylinder block 4. The second communication path 62 extends from a branch point 64 b on the main gallery 64 to a branch part 63 b on the cylinder head 3. The third communication path 63 extends in the horizontal direction between the intake side and the exhaust side in the cylinder head 3. The plurality of oil passages 71 to 79 branch from the third communication passage 63 in the cylinder head 3.

  The oil pump 16 is a known variable capacity oil pump that changes the capacity of the oil pump 16 to vary the oil discharge amount of the oil pump 16, and includes a housing, a drive shaft, a pump element, a cam ring, And a spring and a ring member. The housing has a suction port 16 a for supplying oil to the internal pump chamber 161 and a discharge port 16 b for discharging oil from the pump chamber 161. A pressure chamber 162 defined by the inner peripheral surface of the housing and the outer peripheral surface of the cam ring is formed inside the housing, and an introduction hole 16c is provided in the pressure chamber 162.

  An oil strainer 18 facing the oil pan 5 is provided at the suction port 16 a of the oil pump 16. An oil filter 65 and an oil cooler 66 are arranged in order from the upstream side to the downstream side in the first communication path 61 communicating with the discharge port 16b of the oil pump 16. The oil stored in the oil pan 5 is pumped up by the oil pump 16 through the oil strainer 18, then filtered by the oil filter 65, cooled by the oil cooler 66, and then the main gallery in the cylinder block 4. 64.

  The main gallery 64 rotatably connects a metal bearing oil supply portion 81 disposed on five main journals that rotatably support the crankshaft 7 and four connecting rods 8, and a crankpin of the crankshaft 7. Is connected to an oil supply part 82 of a metal bearing arranged in Oil is constantly supplied to the main gallery 64.

  On the downstream side of the branch point 64 c of the main gallery 64, an oil supply unit 83 that supplies oil to a hydraulic chain tensioner (not shown) of the timing chain, and oil that supplies oil to the pressure chamber 162 of the oil pump 16. The path 70 is connected. The oil passage 70 communicates from the branch point 64 c of the main gallery 64 to the introduction hole 16 c of the oil pump 16, and a linear solenoid valve 89 capable of electrically controlling the oil flow rate is provided in the middle of the oil passage 70.

  The oil passage 78 branched from the branch point 63 a of the third communication passage 63 is connected to the exhaust side first direction switching valve 84, and the advance side oil passage 201 is controlled by the exhaust side first direction switching valve 84. The oil is supplied to the advance working chamber 203 and the retard working chamber 204 of the exhaust VVT 20 to be described later via the retard angle oil passage 202. Further, the oil passage 74 branched from the branch point 63a is connected to the oil supply unit (see the white triangle Δ in FIG. 4), the HLA 15, the HLA 14, the fuel pump 87, and the vacuum pump 88. . The oil passage 76 that branches from the branch point 74 a of the oil passage 74 is connected to an oil shower that supplies lubricating oil to the exhaust-side swing arm 54, and oil is also constantly supplied to the oil passage 76.

  A hydraulic pressure sensor 90 that detects the hydraulic pressure of the oil passage 77 is disposed in the oil passage 77 that branches from the branch point 63 c of the third communication passage 63. The oil passage 73 branched from the branch point 63d is connected to the cam journal oil supply portion (see the white triangle Δ in FIG. 4), the HLA 15 and the HLA 14 in the cam shaft 43 on the intake side. . The oil passage 75 that branches from the branch point 73 a of the oil passage 73 is connected to an oil shower that supplies lubricating oil to the swing arm 44 on the intake side.

  The oil passage 79 that branches from the branch point 63c of the third communication passage 63 is provided with a check valve that restricts the direction in which the oil flows in only one direction from the upstream side to the downstream side. This oil passage 79 branches at the branch point 79a on the downstream side of the check valve into the two oil passages 71, 72 communicating with the mounting holes 45, 55 for the HLA 14 with a valve stop mechanism. The oil passages 71 and 72 stop the valve of the HLA 14 with each valve stop mechanism on the intake side and the exhaust side via the intake side second direction switching valve 86 and the exhaust side second direction switching valve 85 as second hydraulic control valves. Each is connected to the mechanism 14b. By controlling each of the intake side second direction switching valve 86 and the exhaust side second direction switching valve 85, oil is supplied to each valve stop mechanism 14b.

(Phase control mechanism)
In the engine 1, when the reduced cylinder operation is switched, a variable valve timing mechanism (hereinafter abbreviated as VVT) is used to set the opening and closing timings of the intake and exhaust valves 41 and 51 to the retarded side, thereby increasing the combustion gas. The torque is increased and the pumping loss is reduced. The cam pulleys of the intake VVT 19 and the exhaust VVT 20 are driven by a sprocket (not shown) of the crankshaft 7 via a timing chain. As shown in FIG. 4, the intake VVT 19 includes an electric motor 191 and a conversion unit (not shown) formed at one end of the cam shaft 43. The electric motor 191 is integrally formed with a gear pulley that meshes with the timing chain and rotates synchronously with the crankshaft 7, and the conversion portion is integrally formed with the camshaft 43. The phase between the gear pulley (timing chain) and the cam shaft 43 is changed by relatively displacing the conversion unit around the axis with respect to the electric motor 191.

  The exhaust VVT 20 has an annular housing and a vane body accommodated in the housing (both not shown). The housing is coupled to a cam pulley that rotates in synchronization with the crankshaft 7 so as to be integrally rotatable, and rotates in conjunction with the crankshaft 7. The vane body is connected to a camshaft 53 that opens and closes the exhaust valve 51 by a fastening bolt so as to be integrally rotatable. A plurality of advance working chambers 203 and retard working chambers 204 are formed in the housing, which are partitioned by an inner peripheral surface of the housing and a plurality of vanes provided on the outer peripheral surface of the vane body. As shown in FIG. 4, the advance working chamber 203 and the retard working chamber 204 are connected to the exhaust side first direction switching valve 84 via an advance side oil passage 201 and a retard side oil passage 202, respectively. Yes. The exhaust side first direction switching valve 84 is connected to the variable displacement oil pump 16. A part of the advance side oil passage 201 and the retard side oil passage 202 are formed in the cam shaft 53 and the vane body, respectively.

  As shown in FIG. 4, the VVT 20 is provided with a lock mechanism that locks the operation of the VVT 20. The lock mechanism has a lock pin 205 for fixing the phase angle of the camshaft 53 with respect to the crankshaft 7 at a specific phase. Each vane is rotated to an advanced position with respect to the cam pulley (crankshaft 7) by the oil supplied through the advance side oil passage 201, and each vane is turned into the cam pulley by the oil supplied through the retard side oil passage 202. Is rotated to a retard position. Then, the lock pin 205 urged by the urging spring is fitted into a fitting recess formed in a portion of the vane body where the vane is not formed, thereby being locked. As a result, the vane body is fixed to the housing, and the phase of the camshaft 53 relative to the crankshaft 7 is fixed.

  With the above configuration, the amount of oil supplied to the advance working chamber 203 and the retard working chamber 204 of the VVT 20 can be controlled by controlling the exhaust-side first direction switching valve 84. Specifically, when oil is supplied to the advance working chamber 203 with a larger supply amount (higher hydraulic pressure) than the retard working chamber 204 by the control of the exhaust side first direction switching valve 84, the camshaft 53 By rotating in the rotational direction, the opening timing of the exhaust valve 51 is advanced and set to the advance side. On the other hand, when oil is supplied to the retarded working chamber 204 with a larger supply amount (higher hydraulic pressure) than the advanced working chamber 203 by the control of the exhaust side first direction switching valve 84, the camshaft 53 is moved in its rotational direction. Is rotated in the opposite direction, and the opening timing of the exhaust valve 51 is delayed and set to the retarded angle side.

(Control system)
The engine 1 is controlled by an ECU (Electric Control Unit) 110 that is an engine control device.
The ECU 110 normally executes all cylinder operation by the first to fourth cylinders, and when the execution condition for the reduced cylinder operation is satisfied, the ECU 110 stops the operation of the first and fourth cylinders and activates the second and third cylinders. The reduced-cylinder operation is performed. The ECU 110 includes a CPU (Central Processing Unit), a ROM, a RAM, an in-side interface, an out-side interface, and the like. As shown in FIG. 5, the ECU 110 includes a hydraulic pressure sensor 90, a vehicle speed sensor 91, an accelerator opening sensor 92, a gear position sensor 93, an intake manifold pressure sensor 94, an intake air amount sensor 95, and an intake air temperature sensor 96. The intake pressure sensor 97, the crank angle sensor 98, the cam angle sensor 99, the oil temperature sensor 100, the exhaust temperature sensor 101, the water temperature sensor 102, and the traveling equipped on the vehicle so that the driver can select and operate. It is electrically connected to the mode selection switch 103 and the like.

  The vehicle speed sensor 91 detects the travel speed of the vehicle, and the accelerator opening sensor 92 detects the amount of depression of an accelerator pedal (not shown) by the driver. The gear stage sensor 93 detects a transmission gear stage currently set in the transmission mounted on the vehicle, and the intake manifold pressure sensor 94 detects the pressure in the intake manifold. The intake air amount sensor 95 detects the intake air amount, the intake air temperature sensor 96 detects the intake air temperature, and the intake pressure sensor 97 detects the intake air pressure. The crank angle sensor 98 detects the rotation angle of the crankshaft 7 and detects the engine rotation speed based on this rotation angle. The cam angle sensor 99 detects the rotation angle of the cam shafts 43 and 53, and detects the rotation phase of the cam shafts 43 and 53 and the phase angle of each VVT 19 and 20 based on the rotation angle. The oil temperature sensor 100 detects the temperature of oil flowing through the oil passage 70. The exhaust temperature sensor 101 detects the temperature of the exhaust gas flowing through the exhaust pipe 34, and the water temperature sensor 102 detects the temperature of the cooling water that circulates and cools the engine 1. The travel mode selection switch 103 outputs a value corresponding to the travel mode of the vehicle. The detection values from these sensors 90 to 102 are output to the ECU 110 to control the operation of the engine 1.

  This ECU 110 is based on the detected values of the sensors 90 to 102 and the travel mode selection switch 103 so that the total torque output from the engine 1 continues smoothly when switching from one operation to the other operation. The spark plug 13, the HLA 14, the VVTs 19 and 20, the throttle valve 25, and the exhaust shutter valve 35 are coordinated and controlled in time series. As shown in FIG. 5, the ECU 110 includes an operation condition determination unit 111 (operation condition determination unit), a VVT control unit 112, an ignition timing control unit 113, a fuel control unit 114 (fuel control unit), and a throttle. A cylinder deactivation control unit including a valve control unit 115, a valve stop mechanism control unit 116, and an exhaust shutter valve control unit 117, a deceleration fuel supply stop determination unit 118 (deceleration fuel supply stop determination unit), and the like are provided. Yes.

First, the operating condition determination unit 111 will be described.
The operation condition determination unit 111 determines whether or not to execute all-cylinder operation or reduced-cylinder operation based on the operation state. As shown in FIG. 6, the operation condition determination unit 111 stores in advance a map M in which the all-cylinder operation region A1 and the reduced-cylinder operation region A2 are set. Based on the map M and the operation state, any operation is performed. It is determined whether the execution condition is satisfied. In the map M, the horizontal axis is defined by the engine speed, and the vertical axis is defined by the target indicated torque.

  The reduced-cylinder operation region A2 is set in a region range from the lower limit value N1 to the upper limit value N2 for the engine speed, and the reference torque line L that increases according to the engine speed is set to zero torque for the target indicated torque. To the reference torque line L, the region range is set.

  The target indicated torque is a basic torque calculated based on the target acceleration of the vehicle, and the output of the engine 1 and the transmission speed control of the transmission are executed by this basic torque. Specifically, a target acceleration of the vehicle is set based on the accelerator opening, the vehicle speed, and the gear position reflecting the amount of depression of the accelerator pedal using a preset map (not shown), and the wheel torque is determined based on the target acceleration. Is calculated. After calculating the output torque and input torque of the transmission using this wheel torque to obtain the shaft torque necessary for the engine 1, the torque for correction such as auxiliary machine loss and mechanical loss is added to the engine shaft torque to obtain the final torque. Thus, the target indicated torque is obtained. That is, the required torque requested by the driver via the accelerator pedal to the engine 1 is calculated as the target indicated torque based on the accelerator opening and the vehicle state, and the engine 1 is output so that the target indicated torque is output as the total torque. Driving.

  When the coolant temperature of the engine 1 is high, the combustibility is lowered. When the temperature of the hydraulic oil is high, air is likely to be mixed into the hydraulic oil. Followability is reduced. Further, when the exhaust temperature of the engine 1 is high, the reliability of exhaust system members arranged around the exhaust passage such as various sensors and an SCU (Sensor Control Unit) attached to the sensor is lowered. Therefore, the operation condition determination unit 111 is configured to limit the execution of the reduced-cylinder operation based on the water temperature, the oil temperature, and the exhaust temperature.

  The operating condition determination unit 111 stores in advance a water temperature determination temperature T1, an oil temperature determination temperature T2, and an exhaust temperature determination temperature T3. When the water temperature is higher than the water temperature determination temperature T1, or when the oil temperature is the oil temperature determination temperature. When the exhaust temperature is higher than T2 or when the exhaust temperature is higher than the exhaust temperature determination temperature T3, even if the operating state determined by the engine speed and the target indicated torque exists in the reduced-cylinder operating region A2, the reduced-cylinder operation is restricted. doing. The water temperature determination temperature T1 is set based on the combustibility, the oil temperature determination temperature T2 is set based on the response and followability of the operation switching operation, and the exhaust temperature determination temperature T3 is determined by the knocking suppression delay control and the switching delay. Even if the angle control is duplicated, the engine 1 is set to a value that does not misfire.

  The ECU 110 does not immediately execute the reduced-cylinder operation for stopping the first and fourth cylinders even when the operation condition determining unit 111 determines that the execution condition for the reduced-cylinder operation is satisfied, and prepares for executing the reduced-cylinder operation. It is comprised so that a process may be implemented. In the reduced-cylinder operation, the intake and exhaust valves 41 and 51 of the first and fourth cylinders are closed, the VVTs 19 and 20 are set on the retard side, and the opening of the throttle valve 25 is set on the increase side. Therefore, in the preparatory process, the hydraulic pressure is increased to the switching target hydraulic pressure higher than the holding hydraulic pressure supplied to the HLA 14 in order to keep the intake and exhaust valves 41 and 51 of the first and fourth cylinders closed, and the VVT 19 , 20 are controlled to the retard side, and the opening of the throttle valve 25 is controlled to the increase side.

  Here, in order to keep the total torque output from the engine 1 smoothly and smoothly, the ignition timing is controlled to the retard side in the increasing side control period of the throttle valve 25, and in order to suppress deterioration in fuel consumption, In consideration of shortening the retard side control period of the ignition timing, the opening operation of the throttle valve 25 is increased after the target hydraulic pressure increase operation for switching and the retard operation of the VVTs 19 and 20 are completed. Furthermore, since the amount of hydraulic pressure consumed by the retarding operation of the VVT 20 is large, a decrease in the hydraulic pressure supplied to the HLA 14 or a fluctuation in the hydraulic pressure such as overshoot or undershoot occurs, and the operation switching time becomes longer. The target hydraulic pressure increase operation for switching is performed after the end of the retard operation. As described above, when the operating condition determination unit 111 determines that the execution condition for the reduced cylinder operation is satisfied, first, the retard operation of the VVTs 19 and 20 is started.

Next, the VVT control unit 112 will be described.
The VVT control unit 112 sets the target phase for the reduced cylinder operation of the VVTs 19 and 20 based on the air charging efficiency (ce) at the time of operation switching from all cylinder operation to reduced cylinder operation (hereinafter referred to as reduced cylinder operation switching). The electric motor 191 and the exhaust side first direction switching valve 84 are retarded. The VVT control unit 112 gradually controls to the retard side so that the target phase for reduced-cylinder operation becomes the target phase for reduced-cylinder operation when switching to reduced-cylinder operation, and switches the operation from reduced-cylinder operation to all-cylinder operation. (Hereinafter referred to as all-cylinder operation switching), the control is gradually advanced to the advance side so that the target phase for reduced cylinder operation becomes the target phase for all cylinder operation.

Next, the ignition timing control unit 113 will be described.
The ignition timing control unit 113 determines the ignition timing according to the driving state of the vehicle, and outputs an ignition execution command to the spark plug 13. The ignition timing control unit 113 stores in advance an ignition timing map (not shown) set by the engine speed and the engine load substituted by the accelerator opening, and is extracted based on the ignition timing map. The basic ignition timing is set based on the ignition timing and the intake pressure detected by the intake pressure sensor 97. Two types of ignition timing maps are prepared for all cylinder operation and reduced cylinder operation.

  The ignition timing control unit 113 is gradually retarded toward the target basic ignition timing in accordance with the operation of increasing the opening of the throttle valve 25 (the air charging efficiency of each cylinder) at the time of switching the reduced cylinder operation. At the time of all-cylinder operation switching, the target is gradually advanced toward the basic ignition timing at the time of all-cylinder operation in accordance with the decreasing operation of the throttle valve 25. The retard amount during retarded cylinder operation switching and during all cylinder operation switching is set to be inversely proportional to the internal EGR amount flowing into the cylinder bore 9 of each cylinder. The ignition timing retardation control at the time of switching the reduced cylinder operation and at the time of switching all the cylinder operations is once canceled after the start of the reduced cylinder operation, and returned to the retard amount before the cancellation again at the time of switching all the cylinder operations.

Next, the fuel control unit 114 and the throttle valve control unit 115 will be described.
The fuel control unit 114 determines the fuel injection amount and timing according to the operating state, and outputs an injection execution command to the injector 12. The fuel control unit 114 stores a fuel injection map (not shown) preset by the target indicated torque, and sets the fuel injection amount and timing based on this map. The fuel control unit 114 drives the injectors 12 of the first to fourth cylinders during the all-cylinder operation to execute fuel injection, and prohibits the fuel injection of the injectors 12 of the first and fourth cylinders during the reduced-cylinder operation. 2. The fuel injection is executed by driving the injector 12 of the third cylinder. Also, the deceleration fuel supply stop condition described later based on the accelerator opening, the engine speed, the vehicle speed, the gear stage, etc. is satisfied, the deceleration fuel supply is stopped, and the fuel supply return condition described later is satisfied while the deceleration fuel supply is stopped To return.

  The throttle valve control unit 115 controls the opening degree of the throttle valve 25 by operating the actuator 26 so as to realize the target indicated torque. The throttle valve control unit 115 reduces the number of operating cylinders during the reduced cylinder operation, so that the output per cylinder of the operating cylinders (second and third cylinders) is larger than the output per cylinder during the entire cylinder operation. In order to achieve this, the opening degree of the throttle valve 25 is controlled to increase toward the opening side. In addition, the throttle valve control unit 115 starts an operation of increasing the opening of the throttle valve 25 to the target air charging efficiency at the time of the reduced cylinder operation after the completion of the correction control by the VVT 20 when the reduced cylinder operation is switched. At the time of switching, simultaneously with the start of control of the VVTs 19 and 20 to the advance side, the operation of reducing the opening of the throttle valve 25 to the target air charging efficiency during all cylinder operation is started.

Next, the valve stop mechanism control unit 116 will be described.
The valve stop mechanism control unit 116 switches the control of the linear solenoid valve 89 according to whether all cylinder operation or reduced cylinder operation. The valve stop mechanism control unit 116 turns off the linear solenoid valve 89 during all cylinder operation to enable the opening and closing operations of the intake and exhaust valves 41 and 51 of the first to fourth cylinders. The linear solenoid valve 89 is turned on to maintain the hydraulic pressure supplied to the HLA 14 at the closed state holding hydraulic pressure, and the intake / exhaust valves 41 and 51 of the idle cylinders are maintained in the closed state.

  The valve stop mechanism control unit 116 switches the oil pressure by the exhaust side second direction switching valve 85 after the air filling efficiency of each cylinder reaches the target air filling efficiency at the time of the reduced cylinder operation at the time of switching the reduced cylinder operation. And the exhaust valve 51 is closed, and the intake valve 41 is closed by the intake-side second direction switching valve 86 with a slight delay. Further, the valve stop mechanism control unit 116 opens the exhaust valve 51 by the exhaust side second direction switching valve 85 when the all cylinder operation is switched, and takes the intake side by the intake side second direction switching valve 86 slightly later than this. The valve 41 is opened.

Next, the exhaust shutter valve control unit 117 will be described.
The exhaust shutter valve control unit 117 controls the exhaust shutter valve 35 to the closed side during the reduced-cylinder operation, and the exhaust pressure upstream of the exhaust shutter valve 35 is set to the set pressure (for example, the exhaust valve 51) during the all-cylinder operation. The exhaust shutter valve 35 is controlled to be equal to or lower than (seal pressure). The exhaust shutter valve control unit 117 is set so that a predetermined exhaust gas flows when the exhaust shutter valve 35 is in the fully closed position and becomes atmospheric pressure at the fully open position. The pressure can be estimated.

Next, the deceleration fuel supply stop determination unit 118 will be described.
The deceleration fuel supply stop determination unit 118 determines whether a deceleration fuel supply stop condition for stopping the fuel supply during engine deceleration is satisfied. The deceleration fuel supply stop condition is that the accelerator pedal is not depressed and the engine speed is higher than the fuel supply stop speed set in accordance with the vehicle speed and gear position. The deceleration fuel supply stop determination unit 118 determines that the fuel supply return condition is satisfied when the engine speed becomes equal to or less than the fuel supply return speed Nr or when the accelerator pedal is depressed. The fuel supply return rotation speed Nr is set lower than the fuel supply stop rotation speed and in the vicinity of the lower limit value N1 of the rotation speed in the reduced cylinder operation region A2 shown in FIG. Since the fuel supply return rotation speed Nr is adjusted by the oil temperature, the water temperature, etc., it can be either higher or lower than the lower limit value N1.

Next, the contents of the operation condition determination process will be described based on the flowchart of FIG.
Si (i = 101, 102...) Indicates a step for each process.
First, in S101, the output value of each sensor 90-102, each map, and various information are read, and it progresses to S102. Next, in S102, it is determined whether or not the current engine speed is not less than the lower limit value N1 and not more than the upper limit value N2. If the determination is Yes, the process proceeds to S103, and if the determination is No, the process proceeds to S108, where it is determined that the execution condition for all-cylinder operation is satisfied, and the process returns.

  Next, in S103, it is determined whether or not the current target indicated torque (requested torque) is equal to or less than the reference torque line L. If the determination is Yes, the current operating state exists in the reduced-cylinder operating area A2, and the process proceeds to S104. Next, in S104, it is determined whether or not the cooling water temperature is equal to or lower than the water temperature determination temperature T1. If the determination is Yes, the process proceeds to S105. Next, in S105, it is determined whether or not the oil temperature is equal to or lower than the oil temperature determination temperature T2. If the determination is Yes, the process proceeds to S106. Next, in S107, it is determined whether the exhaust temperature is equal to or lower than the exhaust temperature determination temperature T3. When the determination is Yes, it is determined that the reduced-cylinder operation execution condition is satisfied, and the process returns.

  On the other hand, if the determination in S103 is No, the current target indicated torque does not exist in the reduced-cylinder operation region A2 of the map M, so the process proceeds to S108, where it is determined that the execution condition for all-cylinder operation is satisfied, and the process returns. Further, even if the result of the determination in S104 to S106 is No, the operation state is not suitable for the reduced-cylinder operation, so that the process proceeds to S108 and it is determined that the execution condition for all-cylinder operation is satisfied and the process returns.

  When the operating condition determining unit 111 determines that the conditions for executing the reduced cylinder operation are satisfied, the VVT control unit 112, the ignition timing control unit 113, the fuel control unit 114, the throttle valve control unit 115, the valve stop mechanism control unit 116, the exhaust shutter. The valve control unit 117 is actuated to start the reduced cylinder operation switching. Further, when it is determined that the execution condition for all cylinder operation is satisfied, all cylinder operation switching is started. The reduced-cylinder operation switching and all-cylinder operation switching will be described based on the time chart shown in FIG.

  When it is determined at time t1 that the reduced cylinder operation execution condition is satisfied, the VVT retarding operation is performed on the intake and exhaust valves 41 and 51 as a preparation process for switching to the reduced cylinder operation. At time t2, the phase of the exhaust valve 51 is made to reach the target phase for reduced cylinder operation and the hydraulic pressure is raised toward the target hydraulic pressure for switching.

  When the oil pressure in the oil passage 70 reaches the switching target hydraulic pressure at time t3, the exhaust-side first direction switching valve 84 is further operated so as to correspond to the change in the operating state during the pressure increasing operation period, thereby reducing the cylinder operating target. Correct the phase. When the correction target phase for reduced cylinder operation is reached at time t4, the throttle valve increasing operation for increasing the opening of the throttle valve 25 toward the target air charging efficiency and the ignition timing retarding control for retarding the ignition timing are executed. Start.

  After the air filling efficiency exceeds the target air filling efficiency during the reduced cylinder operation at time t5, the valve closing operation of the intake and exhaust valves 41 and 51 is executed. The timing for starting the closing operation of the exhaust valve 51 is started earlier than the timing for starting the closing operation of the intake valve 41. After the intake and exhaust valves 41 and 51 are closed at time t6, the fuel injection of the first and fourth cylinders is prohibited and the ignition timing is restored. Also, adjustment is started from the switching target hydraulic pressure to the valve closing holding hydraulic pressure supplied to the HLA 14. The reduced-cylinder operation is started from time t7 due to the followability of the hydraulic pressure. Therefore, the period between times t5 and t7 is a switching transition period.

  When it is determined at time t8 that the execution conditions for all cylinder operation are satisfied, the prohibition of fuel injection for the first and fourth cylinders is canceled and ignition timing retardation control is started at time t9 in order to execute all cylinder operation switching. To do. The ignition timing retarding control for all-cylinder operation switching is temporarily returned to the ignition timing at the time of switching the reduced-cylinder operation, and the ignition timing at the time of switching the reduced-cylinder operation is set as the initial ignition timing. At this time, since the release of the valve closing operation of the intake and exhaust valves 41 and 51 of the first and fourth cylinders is not completed, the operation of the injector 12 and the spark plug 13 is not started. The opening operation start timing of the exhaust valve 51 is started earlier than the opening operation start timing of the intake valve 41.

  When the hydraulic pressure supplied to the HLA 14 drops from the closed valve holding hydraulic pressure to the target hydraulic pressure during all cylinder operation at time t10, the release operation of the intake and exhaust valves 41 and 51 of the first and fourth cylinders is completed, and all cylinder operation is performed. Is started. Therefore, the period between t8 and t10 is a switching transition period. Further, the throttle valve increasing operation is ended and the opening degree of the throttle valve 25 is gradually decreased, the VVT retarding operation is ended, and the phase of the VVT 20 is gradually controlled to be advanced, and the first and fourth cylinders are controlled. Fuel injection is executed, and advance angle control is executed to gradually control the ignition timing to the advance side. Thereby, the opening degree of the throttle valve 25 reaches the target air charging efficiency in the all cylinder operation at the time t11, and the phase of the VVT 20 reaches the all cylinder operation target phase at the time t12.

  When the driver returns the accelerator pedal for deceleration of the vehicle or the like during all-cylinder operation or reduced-cylinder operation, the engine speed decreases. Control of the deceleration fuel supply stop by this engine deceleration will be described based on the flowchart of FIG. Si (i = 201, 202,...) Represents a step for each process.

  First, in S201, the output value of each sensor 90-102, each map, and various information are read, and it progresses to S202. In S202, it is determined whether a deceleration fuel supply stop condition is satisfied. When determination is No, it progresses to S203, the fuel supply according to the driving | running state is performed, and it returns. If the determination is Yes, the process proceeds to S204, the deceleration fuel supply stop is executed, and the process proceeds to S205.

  In S205, it is determined whether or not the reduced-cylinder operation was performed before the deceleration fuel supply was stopped. If the determination is Yes, the process proceeds to S206, the reduced-cylinder operation is switched to the all-cylinder operation, and the operation flag f is set to 1, and the process proceeds to S208. If the determination in S205 is No, the process proceeds to S207, the operation flag f is set to 0, and the process proceeds to S208.

  In S208, it is determined whether the engine speed in the fuel supply return condition is equal to or less than the fuel supply return speed Nr. If the determination is Yes, the process proceeds to S209, and the fuel supply is restored and the process returns with the all cylinder operation switched in S205. If the determination is No, the process proceeds to S210.

  In S210, it is determined whether or not the accelerator pedal is not depressed in the fuel supply return condition. When the determination is Yes, the process proceeds to S211 and the fuel supply stop is continued with the all cylinder operation switched in S205, and the process returns. If the determination is No, the process proceeds to S212.

  In S212, it is determined whether or not the operation flag f is 1. When the determination is Yes, the process proceeds to S213, the reduced-cylinder operation is performed, the fuel supply is restored, and the process returns. If the determination is No, the process proceeds to S214, the fuel supply is returned with the all cylinder operation switched in S205, and the process returns.

Next, the operation and effect of the engine control apparatus will be described.
As described above, during the reduced-cylinder operation, the operation is switched to the all-cylinder operation in a state where the fuel supply is stopped when the reduced-side fuel supply stop condition is satisfied. After that, as long as the accelerator pedal is not depressed until the speed is reduced to the fuel supply return speed Nr, the fuel supply stop state in the all cylinder operation is continued. When the engine 1 decelerates to the fuel supply return rotational speed Nr or less, the fuel supply is returned in the all-cylinder operation so that the engine 1 does not stop. Therefore, it is possible to prevent the switching to the all-cylinder operation and the return of fuel supply from continuing at the same time after stopping the deceleration fuel supply, and the occurrence of torque shock can be suppressed. Further, since the fuel supply return rotation speed Nr is set in the vicinity of the lower limit value N1 of the rotation speed in the reduced-cylinder operation area A2, the engine rotation speed area in which the deceleration fuel supply can be stopped can be widened.

  If the accelerator pedal is depressed before decelerating to the fuel supply return rotational speed Nr, if the reduced-cylinder operation is before the deceleration fuel supply stop, the reduced-cylinder operation is returned to return the fuel supply. On the other hand, when the all-cylinder operation is before the deceleration fuel supply is stopped, the fuel supply is returned by the all-cylinder operation. Therefore, during the reduced cylinder operation, the reduced cylinder fuel supply stop condition is satisfied, and after switching to the all cylinder operation in the deceleration fuel supply stop state, the reduced cylinder operation is resumed in the deceleration fuel supply stop state. be able to. Further, since the switching to the all-cylinder operation and the fuel supply return are not continued at the same time, torque shock can be suppressed.

  In the above embodiment, an example of an in-line four-cylinder gasoline engine has been described. However, the present invention can be applied without being limited to an engine type such as a six-cylinder engine or a V-type engine. It is not limited to engines. Further, the example of the engine that performs the reduced cylinder operation in which half of the four cylinders are deactivated has been described, but the number of deactivated cylinders may be arbitrarily set.

  In addition, those skilled in the art can implement the present invention in a form in which various modifications are added to the above-described embodiment or a combination of the above-described embodiments without departing from the spirit of the present invention. The form is also included.

1 Engine 91 Vehicle speed sensor 92 Accelerator opening sensor 93 Gear speed sensor 98 Crank angle sensor 100 Oil temperature sensor 103 Traveling mode selection switch 110 ECU
111 Operating condition determination unit 114 Fuel control unit 118 Deceleration fuel supply stop determination unit A1 All cylinder operation region A2 Reduced cylinder operation region L Reference torque line M Map T1 Water temperature determination temperature T2 Oil temperature determination temperature T3 Exhaust temperature determination temperature

Claims (4)

Operating condition determining means for determining an execution condition for reduced-cylinder operation of an engine having a plurality of cylinders, deceleration fuel supply stop determining means for determining deceleration fuel supply stop conditions, and fuel control means for controlling fuel supply to the engine A cylinder deactivation control means for switching from all-cylinder operation to reduced-cylinder operation when an execution condition for reduced-cylinder operation is satisfied,
When it is determined by the operating condition determination means and the deceleration fuel supply stop determination means that the deceleration fuel supply stop condition during the reduced cylinder operation is satisfied, the fuel control means stops the fuel supply and the cylinder deactivation control means decreases. An engine control device that switches from cylinder operation to the all cylinder operation. The fuel control means returns the fuel supply when the engine decelerates below the fuel supply return rotational speed,
2. The engine control device according to claim 1, wherein the fuel supply return rotational speed is set in the vicinity of a lower limit of an engine rotational speed in an execution condition of the reduced-cylinder operation.   The switch to the reduced-cylinder operation is performed when the accelerator pedal is depressed after the reduced-cylinder operation is switched to the all-cylinder operation and before the fuel supply is returned by the fuel control unit. Engine control device.   4. The engine control device according to claim 3, wherein the fuel supply is restored by the fuel control means after switching to the reduced-cylinder operation.